Converts an array of JSON objects to a CSV string, with a header (assuming complete objects as from a database). Does not use Object.keys.

JSONtoCSV.js

// Converts an array of JSON objects a CSV string.
function JSONtoCSV(jsonArray) {
  var csv = '';
  var header = '';

  for (var i = 0; i < jsonArray.length; i += 1) {
    var entry = '';
    var obj = jsonArray[i];

    for (var property in obj) {
      if (obj.hasOwnProperty(property)) {

        // Create header.
        if (i == 0) {
          if (header != '') header += ','

          header += property
        }

        // Comma-split unless line is empty.
        if (entry != '') entry += ','

        entry += jsonArray[i][property];
      }
    }

    csv += entry + '\r\n';
  }

  csv = header + '\r\n' + csv;
  return csv;
}